1. Technical Field
The present invention relates to a liquid ejecting head including a piezoelectric element having a piezoelectric body layer and electrodes provided in both sides thereof, a liquid ejecting apparatus, a piezoelectric element and a sensor.
2. Related Art
In a piezoelectric element used in an ink jet type recording head or the like which is known as a representative example of a liquid ejecting head, in order to practically increase piezoelectric properties of a piezoelectric body layer, it is preferable that the piezoelectric body layer be oriented in a (100) plane when a crystal system thereof is a rhombohedral system. Then, for example, in order to orient lead zirconate titanate (PZT) in the (100) plane, a technology using titanium species in the piezoelectric body layer is known and, for example, a method for manufacturing the piezoelectric element is disclosed in JP-A-2002-83937 in which after a first layer of the piezoelectric body layer is formed on a lower electrode through a titanium layer, the lower electrode is patterned with the piezoelectric body layer of the first layer and a titanium layer is further formed on the piezoelectric body layer of the first layer and a vibration plate, and then remaining piezoelectric body layers are formed. In addition, a technology using lanthanum nickel oxide (LNO) instead of the titanium layer as an orientation control layer is also known (for example, JP-A-2004-066600 or the like). Furthermore, a technology in which a buffer layer configured of a metal element capable of forming a B site of a PZT crystal is oriented in (100) as a seed layer is also suggested (see JP-A-2005-340428).
However, when manufacturing the ink jet type recording head, the piezoelectric body layer is also deposited on an insulator layer of silicon oxide, zirconium oxide or the like of a ground thereof in addition to on the lower electrode. The seed layer made of the titanium species, LNO and the metal element described above may not be effectively oriented by influence of the ground. Therefore, there is a problem that an orientation state is varied by the ground, thereby decreasing displacement characteristics or durability thereof.
On the other hand, a lead-free piezoelectric material or a piezoelectric material in which content of lead is reduced is required in consideration of environmental issues. As the piezoelectric material in which lead is not contained, for example, there is a piezoelectric material of BiFeO3 system containing Bi and Fe (for example, JP-A-2007-287745); however, the problem of the orientation control described above is also present in the piezoelectric material.
In any case, appearance of the orientation control layer is desired in which various piezoelectric materials can be effectively oriented in the (100) plane without being affected by the ground.
In addition, such a problem is, of course, similarly present in other liquid ejecting heads ejecting droplets other than ink in addition to the ink jet type recording head, and is also similarly present in a piezoelectric element or a piezoelectric actuator which is used others other than the liquid ejecting head.